[PD] Does Pd have a "sound"?

Claude Heiland-Allen claude at mathr.co.uk
Mon Feb 15 15:57:36 CET 2016

On 14/02/16 22:27, Matti Viljamaa wrote:
> Do you think Pd has a characteristic sound to it? Or whether
> discussion board threads claiming Pd (and Max) have a distinct (and
> not good) sound just have people who haven’t listened to good
> patches?

Some issues with Pd that affect sound character:

1. cos~ (and osc~) use a small table with linear interpolation, which 
means there is quite a lot of interpolation noise - I wrote about it 
here: http://mathr.co.uk/blog/2015-04-21_approximating_cosine.html

2. vcf~ (and probably other recursive filters) use single precision 
floating point in the feedback loop (pd-double might be different) which 
causes weird rounding artifacts - I wrote about it here: 

3. cubic interpolation (tabread4~ etc) in Pd uses an (imho) incorrect 
algorithm - it makes a curve that goes through 4 points instead of 
matching the derivatives at the nearest 2 points, which leads to sharp 
corners at the original sample points with associated aliasing artifacts 
- this has been discussed on the lists many times in the past, for 
example here: 
http://lists.puredata.info/pipermail/pd-list/2008-06/062864.html and: 

4. sig~ (and implicit sig~ from float messages to signal inlets) is 
steppy and only takes effect at block boundaries - compare with .kr in 
SC3 which is (afaik) linearly interpolated between each block boundary

5. Pd doesn't print enough digits to perfectly reconstruct floating 
point values when round-tripping through files, so (eg) biquad~ 
coefficients can become imprecise if you don't write them outside Pd in 
a text editor

6. other systems tend to come bundled with more nice-sounding stuff like 
bandlimited oscillators etc, with Pd you tend to have to find externals 
yourself (deken should make that easier now)


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